1. Field of the Invention
The present invention relates to lids, and more particularly, to a lid for use in a micro-electro-mechanical device to have an enhanced shielding effect upon the micro-electro-mechanical device and a method for fabricating the same.
2. Description of the Prior Art
Micro-electro-mechanical devices, such as microphones, are in wide use in mobile communication devices, audio devices, etc. To achieve miniaturization, microphones for use as hearing aid units, typically known as condenser microphones, are downsized. However the transducers therein are fragile and susceptible to physical damage. Furthermore, since signal transmission is subject to be interfered with by the environment, the transducer must be protected from light and electromagnetic interferences. Moreover, favorable acoustic pressure is required for the transducer to function properly, as far as prevention of light and electromagnetic interference is concerned. Please refer to FIG. 1 for condenser microphones in wide use.
Referring to FIG. 1, a conventional condenser microphone comprises: a first substrate 10, a conductive plate 11 coupled to the first substrate 10 by means of a conductive adhesive layer 13, and a second substrate 12 coupled to the conductive plate 11 by means of another conductive adhesive layer 13′. The first substrate 10 comprises a mold plate 100 and a backboard 101, and so does the second substrate 12. An auditory aperture 102 is formed in the first substrate 10. A semiconductor chip 14 is mounted on the first substrate 10. Also, a transducer 15 above the auditory aperture 102 is mounted on the first substrate 10. A through cavity 110 formed in the conductive plate 11 not only provides room for different acoustic pressures but also receives the semiconductor chip 14 and the transducer 15.
The conventional condenser microphone provides a protective space defined by the first substrate 10, the through cavity 110 of the conductive plate 11, and the second substrate 12, so as to insulate the semiconductor chip 14 and the transducer 15 and achieve the shielding effect. However, the conductive adhesive layer 13 and the conductive plate 11 differ from each other in constituents, thus deteriorating the shielding effect of the side surface of the condenser microphone.
Accordingly, an issue that calls for immediate solution involves endeavors to overcome the aforesaid drawbacks of the prior art.